Elasticity Questions: Paper 03

<<Previous More PHYSICS Questions
Downlaod () Click here Pages: 2, Size: 35.48 KB, Filetype: pdf

1.

The magnitude of the force developed by raising the temperature from 0 °C to 100 °C of the iron bar of 1.00 m long and 1 cm2 cross-section when it is held so that it is not permitted to expand or bend is

(a = 10-5/°C and Y = 1011 N/m2(CPMT 91)

(a)    103 N                    (b)      104 N

(c)    105                       (d)      109 N

Answer: (b)

2.

Theoretical value of Poisson’s ratio lies between

(AIIMS 85)

(a)    - 1 to 0.5              (b)      -1 to -2

(c)    0.5 to 1                 (d)      None

Answer: (a)

3.

One end of a uniform wire of length L and of weight W is attached rigidly to a point on the roof and a weight W1 is suspended from its lower end. If S is the area of cross-section of the wire, the stress in the wire at a height from its lower end is, (IIT 92)

(a)                          (b)     

(c)             (d)     

Answer: (c)

4.

There is no change in the volume of a wire due to change in its length on stretching. The poison’s ration of the material of the wire is (MHT-CET 2004) 

(a)    + .50                     (b)      - 0.50

(c)    0.25                      (d)      - 0.25

Answer: (b)

5.

A stretched wire has a Young’s modulus Y and energy density E. the strain in the stretched wire is

(a)                        (b)     

(c)                          (d)     

Answer: (a)

6.

Strain has

(a)    No units but only dimensions                      

(b)    Only units but no dimensions

(c)    No units, no dimensions but a constant value                       

(d)    No units, no dimensions but a variable value

Answer: (d)

7.

A stretching wire has a Young’s modulus Y and energy density E. the strain in a stretching wire is

(MHT-CET-2006)

(a)                           (b)     

(c)                         (d)     

Answer: (d)

8.

The change in the shape of a regular boy is due to (Andhra medical 80)

(a)    Bulk strain             (b)      Shearing strain

(c)    Longitudinal strain  (d)      Volume strain

Answer: (b)

9.

When impurities are added to an elastic substance, its elasticity

(a)    Increases             

(b)    Decreases

(c)    Becomes zero                 

(d)    May increase or decrease

Answer: (d)

10.

To compress a liquid by 10% of its original volume, the pressure required is 2 ´ 105 atmosphere. The bulk modulus of liquid is (MHT-CET-2004)

(a)    2 ´ 105 N/m2         (b)      2 ´ 107 N/m2

(c)    2 ´ 104 N/m2         (d)      2 ´ 106 N/m2

Answer: (d)

11.

The upper end of wire 1 m long and 2 mm radius is clamped. The lower end is twisted through an angle of 45°. The angle  of shear is

(NCERT 90 PMT MP 90, 96)

(a)    0.09°                     (b)      0.9°

(c)    9°                         (d)      90°

Answer: (a)

12.

Longitudinal strain is possible in the case of

(a)    Gases                    (b)      Liquid

(c)    Only solids             (d)      Only gases & liquids

Answer: (c)

13.

Which of the following is correct statement from the given graph plotted, for four wires of same material and same thickness  (MHT-CET-2001)

                        

(a)    A has largest length

(b)    D has largest length

(c)    C has largest length        

(d)    B has largest length

Answer: (a)

14.

Relation between y, n, k is (MHT-CET-2008)

(a)               (b)     

(c)              (d)     

Answer: (c)

15.

When the intermolecular distance increases due to tensile force, then

(a)    There is no force between the molecules                 

(b)    There is a repulsive force between the molecules

(c)    There is an attractive force between the molecules              

(d)    There is zero resultant force between the molecules

Answer: (c)

16.

If a material is heated and annealed, then its elasticity is

(a)    Increased              (b)      Decreased

(c)    Not change            (d)      Becomes zero

Answer: (b)

17.

A long string is stretched by 2 cm and the potential energy is V. if the spring is stretched by 10 cm. its potential energy will be (CPMT 76)

(a)                           (b)     

(c)    5V                        (d)      25V

Answer: (d)

18.

The radii of two wires of a same material are in ratio 2:1. if the wires are stretched by equal forces, the stress produced in them will be (MHT CET 2005)

(a)    2:1                       (b)      4:1

(c)    1:4                       (d)      1:2

Answer: (c)

19.

The bulk modulus of elasticity of the material of a metal sphere is 2 × 1011 N/m2. in open air, atmospheric pressure of 105 N/m2 acts on it. What is the fractional decrease in its volume if it kept in a vacuum chamber?

(a)    2 × 10-7                (b)      3 × 10-7

(c)    4 × 10-7                (d)      5 × 10-7

Answer: (d)

20.

The Poisson’s ratio of the material of a wire is 0.25. if it is stretched by a force F, the longitudinal strain produced in the wire is 5 × 10-4. What is the percentage increase in its volume?

(a)    0.2                        (b)      2 × 102

(c)    Zero                      (d)      1.25 × 10-6

Answer: (c)

21.

The bulk modulus of a gas is 6 ´ 103 N/m2. the additional pressure needed to reduce the volume of the liquid by 10% is (MHT-CET-2007)

(a)    1200 N/m2             (b)      600 N/m2

(c)    2400 N/m2             (d)      1600 N/m2

Answer: (b)

22.

Hooke’s law essentially defines  (PMTMP 88)

(a)    Stress                   (b)      Strain

(c)    Yield point             (d)      Elastic limit

Answer: (d)

23.

Strain energy per unit volume is given by

(MHT-CET 2003)

(a)           (b)     

(c)               (d)      None of these

Answer: (a)

24.

The Young’s modulus for a plastic body is

(a)    One                      (b)      Zero

(c)    Infinity                   (d)      Less then one

Answer: (b)

25.

Four steel wires of the following dimensions are stretched with the same force. Which one of them will have the largest extension?

(a)    L1 = 50 cm, r1 = 0.5 mm                 

(b)    L2 = 100 cm, r2 = 1 mm

(c)    L3 = 200 cm, r3 = 2 mm                  

(d)    L4 = 300 cm, r4 = 3 mm

Answer: (a)